I cannot believe that I posted this back in September and only now have they got to the moon. What the (bleep) have they been doing since then for 144 days. It takes 4 days to get to the moon with Apollo rockets and I assume they have made some advances in science in the meantime after more than 40 years.

I must be really stupid too - I was hoping for a few pictures of the moon as they approached, but all we have as of today (02 Feb 2012) is a bunch of images about the launch and an artists impression of the two spacescraft.

This is all very strange.... and why the rush? Often we are told that there are so few space windows that spacecraft can only launch a relatively few times a year. Now suddenly there is ample opportunity.

NASA is to launch Thursday a $500 million pair of unmanned spacecraft that will chase each other around the Moon as they use gravity tools to map its inner core for the first time.

Scientists hope the satellites will help solve mysteries about how the Moon formed, how the unexplored far side differs from the near side which humans have walked on, and whether there was once another Moon that melded with ours.

The GRAIL (Gravity Recovery And Interior Laboratory) mission, aims to launch on a single Delta II rocket as early as 8:37 am Thursday (1237 GMT). A second launch window opens at 9:16 am (1316 GMT).

If weather delays the attempt -- and it might with forecasters predicting just a 40 percent chance of favorable conditions for launch -- other opportunities are available over the next 42 days.

Despite 109 past missions to study the Moon, and the fact that 12 humans have walked on its surface since the dawn of the space age in 1959, GRAIL program scientist Bobby Fogel said there has never been a serious attempt to peer inside.